Radiation-sensitive resin composition, polymer, and method for forming resist pattern

Abstract

A radiation sensitive resin composition capable of forming a photoresist film which has excellent basic resist performances concerning sensitivity, LWR, development defects, etc., gives a satisfactory pattern shape, has an excellent depth of focus, is reduced in the amount of components dissolving in a liquid for immersion exposure which is in contact with the film during immersion exposure, has a large receding contact angle with the liquid for immersion exposure, and is capable of forming a microfine resist pattern with high accuracy. The radiation sensitive resin composition contains (A) a polymer that comprises a repeating unit represented by formula (1) and a repeating unit having a fluorine atom and has an acid dissociable group in the side chain, and (B) a solvent. [In the formula (1), R 1 represents a hydrogen atom, methyl, or trifluoromethyl; and Z represents a group including a structure that generates an acid upon light irradiation.]

1 . A radiation sensitive resin composition, comprising:
 (A) a polymer comprising a repeating unit represented by the following general formula (1) and a repeating unit having a fluorine atom (provided that said repeating unit represented by the general formula (1) is excluded), and having an acid dissociable group in the side chain; and   (B) a solvent.   
       
         
           
           
               
               
           
         
       
       (In the general formula (1), R 1  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and Z represents a group having a structure which generates an acid when exposed to radiation.) 
     
     
         2 . The radiation sensitive resin composition according to  claim 1 , wherein said polymer (A) further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (2), a repeating unit represented by the following general formula (3), and a repeating unit represented by the following general formula (4). 
       
         
           
           
               
               
           
         
       
       (In the general formula (2), R 2  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 3  represents a linear or branched alkyl group having 1 to 4 carbon atoms, m represents an integer of 1 to 3, and n represents an integer of 1 to 3.) 
       
         
           
           
               
               
           
         
       
       (In the general formula (3), R 4  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 5  represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched fluorinated alkyl group having 1 to 4 carbon atoms, or a linear or branched alkoxyl group having 1 to 4 carbon atoms, q represents an integer of 0 to 3, B represents a single bond, an ether group, an ester group, a carbonyl group, a divalent chained hydrocarbon group having 1 to 30 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or a divalent group obtained by combination thereof.) 
       
         
           
           
               
               
           
         
       
       (In the general formula (4), R 6  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 7  each independently represents a hydrogen atom, a chained hydrocarbon group having 1 to 5 carbon atoms, A represents a single bond, a divalent or trivalent chained hydrocarbon group having 1 to 30 carbon atoms, a divalent or trivalent alicyclic hydrocarbon group having 3 to 30 carbon atoms, or a divalent or trivalent aromatic hydrocarbon group having 6 to 30 carbon atoms; when A is trivalent, a carbon atom included in A and a carbon atom constituting the cyclic carbonic acid ester bind to each other thereby to form a ring structure, and n represents an integer of 2 to 4.) 
     
     
         3 . The radiation sensitive resin composition according to  claim 1 , wherein said polymer (A) comprises, as said repeating unit having a fluorine atom, a repeating unit which has in the side chain, a fluorine atom and an acid dissociable group, as represented by the following general formula (P-1). 
       
         
           
           
               
               
           
         
       
       (In the general formula (P-1), n represents an integer of 1 to 3, R 11  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 12  represents a single bond, or a linear, branched, or cyclic, and saturated or unsaturated hydrocarbon group having (n+1) valency with 1 to 10 carbon atoms, R 13  represents a single bond or a divalent linear, branched or cyclic, and saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, X represents a methylene group substituted with a fluorine atom, or a linear or branched fluoroalkylene group having 2 to 20 carbon atoms, Y represents a single bond or —CO—; when n is 1, R 14  represents an acid dissociable group; when n is 2 or 3, R 14  each independently represents a hydrogen atom or an acid dissociable group, and at least one R 14  is an acid dissociable group.) 
     
     
         4 . The radiation sensitive resin composition according to  claim 1 , wherein said polymer (A) comprises, as said repeating unit having a fluorine atom, a repeating unit which has a fluorine atom in the side chain, as represented by the following general formula (P-2), and wherein said polymer (A) further comprises a repeating unit having an acid dissociable group in the side chain, as represented by the following general formula (Q-1). 
       
         
           
           
               
               
           
         
       
       (In the general formula (P-2), R 15  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 16  represents a linear or branched alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, an alicyclic hydrocarbon group having 4 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, or a group derived therefrom.) 
       
         
           
           
               
               
           
         
       
       (In the general formula (Q-1), R 17  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 18  each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a group derived therefrom, or any two of R 15  bind to each other and form, together with the carbon atom to which they are attached, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a group derived therefrom, and the remaining one R 18  represents a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a group derived therefrom.) 
     
     
         5 . The radiation sensitive resin composition according to  claim 1 , wherein said repeating unit represented by the general formula (1) is at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (1-1) and a repeating unit represented by the following general formula (1-2). 
       
         
           
           
               
               
           
         
       
       (In the general formula (1-1), R 21  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 22 , R 23  and R 24  each independently represent a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent group, a linear or branched alkoxyl group having 1 to 10 carbon atoms which may have a substituent group, or an aryl group having 3 to 10 carbon atoms which may have a substituent group, n represents an integer of 0 to 3, A represents a methylene group, a linear or branched alkylene group having 2 to 10 carbon atoms, or an arylene group having 3 to 10 carbon atoms, X −  represents a counter ion of S + .) 
       
         
           
           
               
               
           
         
       
       (In the general formula (1-2), R 25  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, Rf represents a fluorine atom or a linear or branched perfluoroalkyl group having 1 to 10 carbon atoms, A 1  represents a single bond, or a divalent organic group, and M m+  represents a metal ion or an onium cation, m represents an integer of 1 to 3, and n represents an integer of 1 to 8.) 
     
     
         6 . A polymer comprising a repeating unit represented by the following general formula (1) and a repeating unit having a fluorine atom (provided that said repeating unit represented by the general formula (1) is excluded), and having an acid dissociable group in the side chain. 
       
         
           
           
               
               
           
         
       
       (In the general formula (1), R 1  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and Z represents a group having a structure which generates an acid when exposed to radiation.) 
     
     
         7 . The polymer according to  claim 6 , further comprising at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (2), a repeating unit represented by the following general formula (3), and a repeating unit represented by the following general formula (4). 
       
         
           
           
               
               
           
         
       
       (In the general formula (2), R 2  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 3  represents a linear or branched alkyl group having 1 to 4 carbon atoms, m represents an integer of 1 to 3, and n represents an integer of 1 to 3.) 
       
         
           
           
               
               
           
         
       
       (In the general formula (3), R 4  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 5  represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched fluorinated alkyl group having 1 to 4 carbon atoms, or a linear or branched alkoxyl group having 1 to 4 carbon atoms, q represents an integer of 0 to 3, B represents a single bond, an ether group, an ester group, a carbonyl group, a divalent chained hydrocarbon group having 1 to 30 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or a divalent group obtained by combination thereof.) 
       
         
           
           
               
               
           
         
       
       (In the general formula (4), R 6  represents a hydrogen atom, a methyl group, or a trifluoromethyl group, R 7  each independently represents a hydrogen atom, a chained hydrocarbon group having 1 to 5 carbon atoms, A represents a single bond, a divalent or trivalent chained hydrocarbon group having 1 to 30 carbon atoms, a divalent or trivalent alicyclic hydrocarbon group having 3 to 30 carbon atoms, or a divalent or trivalent aromatic hydrocarbon group having 6 to 30 carbon atoms; when A is trivalent, a carbon atom included in A and a carbon atom constituting the cyclic carbonic acid ester bind to each other thereby to form a ring structure, and n represents an integer of 2 to 4.) 
     
     
         8 . A method for forming a resist pattern, comprising,
 (1) forming a photoresist film on a substrate by using said radiation sensitive resin composition according to  claim 1 ,   (2) subjecting said photoresist film to a liquid immersion exposure process, and   (3) developing the photoresist film obtained after said liquid immersion exposure process to form a resist pattern.